Our primary goal is to evaluate the short-term safety and potential efficacy of oyster mushrooms (Pieurotus ostreatus) for treatment of hyperlipidemia in HIV-infected patients who are taking ritonavir, a protease inhibitor (PI) that is commonly used in highly active antiretroviral therapy (HAART). While PIs have conferred significant clinical and survival benefits to patients with HIV, some Pls (especially ritonavir) cause hyperlipidemia in many patients. Standard treatments for hyperlipidemia include the HMG CoA reductase inhibitors or "statins." Unfortunately, many PIs and statins share a common metabolic pathway that uses the CYP3A4 enzyme. Consequently, concomitant administration of ritonavir with most statins increases statin levels significantly, thus increasing the likelihood for adverse effects. Oyster mushrooms have been studied extensively in animal models and have been found to decrease lipid levels - a finding that has been supported by preliminary data in a study in humans. Although these data appear promising, we do not know if oyster mushrooms would have a similar effect in HIV patients with hyperlipidemia who are taking a ritonavir-containing HAART regimen. Nor do we know if there is the potential for significant metabolic interactions with ritonavir or whether the concomitant administration of ritonavir and oyster mushrooms increases the likelihood of adverse effects. We propose to conduct a single-arm, open-label, 8-week "proof of concept" pilot study in 20 subjects to determine if we can detect any lipid-lowering effects of oyster mushrooms in patients with HIV and hyperlipidemia who are taking Kaletra (a ritonavir-containing HAART regimen), to assess whether the concomitant administration of oyster mushrooms and such regimens is safe, and to investigate the mechanism of action whereby oyster mushrooms may exert their hyperlipidemic effect. We will test the following 4 hypotheses: (1) Subjects with hyperlipidemia will have a reduction in non-HDL-cholesterol during the 8-week pilot study; (2) Oyster mushroom will not alter the hepatic metabolism of Kaletra, thus not increasing its toxicity or decreasing its efficacy; (3) There will be no laboratory or clinical toxicities associated with the daily ingestion of dried oyster mushrooms; and (4) There will be measurable plasma levels of HMG CoA reductase inhibition activity. Data from this pilot study will enable us to determine if further investigation is warranted and, if so, to calculate a sample size for a randomized, controlled trial to evaluate the longer term safety and efficacy of dried oyster mushrooms for treatment of hyperlipidemia in this population.